It is anticipated that in some countries at least it will be a requirement in the future that detergent powder should be free from phosphorus. One of the options for making a phosphorus-free detergent composition is to replace the normal phosphate detergency builder with a non-phosphate builder material such as an aluminosilicate, for example a zeolite, and that has been done at least partially in some countries. One of the problems which adoption of aluminosilicates introduces is that of ensuring that the powder has adequate structure. Not only is the inherent capacity of aluminosilicate detergency builders to structure powders lower than that of the sodium tripolyphosphate which it replaces, but it is extremely difficult to use sodium silicate, a powerful powder structurant. Sodium silicate leads to the formation of insoluble silicate/aluminosilicate aggregates which can give undesirable deposits on clothes. Consequently, we have been looking for alternative powder structurants.
We are aware of GB-A-1568420 (Colgate-Palmolive Company) which discloses the use of water-soluble organic materials, including sugars, as binding agents for aluminosilicate detergency builder materials, such as finely divided zeolites to improve the handling properties thereof.
This prior art is concerned primarily with the granulation of zeolite powder with binding agents to form detergent additives suitable for adding to spray dried particles containing other ingredients including a surfactant system. While reference is made to the possible formation of these additives by spray-drying, other methods are preferred and the possibility that any of the binding agents mentioned could perform as structurants of spray-dried powders which contain both the zeolite and a surfactant system is not foreseen.
We have now surprisingly discovered that spray dried powders containing non-phosphate detergency builder materials and having satisfactory dispersibility properties can be produced by the use of specific structurants.